Fluid type inertia device



June 15, 1943. c. c. FARMER FLUID TYPE INERTIA DEVICE Filed Aug. 29, 1942 6 Sheets-Sheet l ATTORNEY INVENTOR Clyde 0 Farmer BY June 15, 1943. c. c. FARMER 2,322,003

FLUID TYiE IQERTIA DEVICE Filed Aug. 29, 1942 6 Sheets-Sheet 2 fig. 5

INVENTOR Clyde 6? Farmer BY m 9 ATTORNEY June 15, 1943.- c. c. FARMER ,3

FLUID TYPE 'INERTIA DEVICE Filed Aug. 29, 1942 6 Sheets-Sheet 3 I CZyde 6. Farmer ATTORNEY June 15, 1943.

c. c. FARMER FLUID TYPE INER'I'IA' DEVICE Filed Aug. 29, 1942 6 Sheets-SheetA INVENTOR glyde Cf Farm 9- -----u ATTORNEY June 15, 1943; c. c. FARMER 2,322,003

FLUID TYPE INERTIA' DEVICE F iled Aug. 29, 1942 6 Sheets-Sheet 5 INVENT OR Clyde 6. Farmer BY ATTORNEY June 15, 1943. c. c. FARMER 2,322,003

FLUID TYPE INERTIA DEVICE Filed Aug. 29, 1942 s Sheets-Shet s INVENTOR Clyde Cf Farmer BY 9 Qu-u ATTORNEY UNITED STATES PATENT OFFICE FLUID TYPE INERTIA DEVICE Clyde C. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application August 29, 1942, Serial No. 456,688

28 Claims.

This invention relates to fluid type inertia devices for detecting the rate of change of speed of a rotary element, such as a railway car wheel or wheel and axle assembly, for a desired indieating or control purpose.

In Patent 2,225,716 to Everett P. Sexton there is disclosed and claimed a fluid type inertia device illustratively applied to the end of a railway car wheel axle and operative in response to the slipping condition of the wheels to cause a rapid release of the brakes associated with the wheels, whereby to cause a restoration of the slipping wheels back to a speed corresponding to car speed before the wheels decelerate to a locked condition and slide.

In the present application, the term slipping condition as applied to a car wheel refers to the rotation of the Wheel at a speed either less or greater than a speed corresponding to car speed at a given instant, due to the application of excessive braking or propulsion torque, respectively, sufficient to exceed the limit of adhesion between the wheels and the rail. As is well known, when the brakes are applied to a vehicle wheel to a degree sufficient to exceed the limit of adhesion between the wheel and the rail, the Wheel decelerates at an abnormally rapid rate far in excess of the maximum normal rate, which is of the order of three to four miles per hour per second. The rotative deceleration of a vehicle wheel at a rate exceeding a certain rate in excess of the normal rate is thus positive indication of a slipping condition of the wheel.

The fluid inertia device shown in the Sexton patent detects the slipping condition of a vehicle wheel due to excessive braking by registering the rate of rotative deceleration of the car wheel at a rate exceeding seven miles per hour.

The term sliding condition, as employed herein in connection with a car wheel, refers to the dragging of the car wheel along the rail in a locked or non-rotative condition. The sliding of a car wheel produces fiat spots on the wheel which is objectionable because this necessitates repair or replacement of the wheel.

Essentially, the device disclosed in the Sexton patent comprises a member, such as a pipe, forming an annular passage and so mounted on the end of a car wheel axle that the annular passage rotates in coaxial relation to the axis of rotation of the axle. The annular passage is provided Interposed between the outer closed ends of the Sylphons is a follower which actuates a contact or switch lever pivoted on the passage member or an equivalent member rotated with the axle.

Whenever the axle accelerates or decelerates, the inertia force or force of momentum of the annular body of mercury is exerted on the closed end of one or the other of the Sylphons, causing pivotal movement of a switch lever to close one or more switches dependent upon the degree of displacement of the switch lever out of its normal centered position.

The Sylphons in the Sexton device are subject to severe shocks and jars transmitted thereto from the car axle during travel of the car. Moreover at high rotational speeds of the axle the Sylphons are also subject to high stress due to high centrifugal forces of the mercury. These Sylphons must, therefore, be mechanically strong enough to withstand the stresses exerted thereon and at the same time flexible enough to permit the expansion and contraction thereof in response to the inertia forces of the mercury.

It is accordingly an object of my present invention to provide a fluid type inertia device, of the type shown in the Sexton patent, characterized by a novel arrangement for supporting the Sylphons in a manner to reduce the possibility of mechanical failure of the Sylphons due to stresses exerted thereon by centrifugal force of the mercury or by shocks and jars on the axle.

It is a further object of my invention to provide a fluid type inertia device which avoids the difliculties inherent in the use of the Sylphons in a fluid type inertia device, such as that shown in the Sexton patent, by providing a construction which does not employ Sylphons.

In the fluid type inertia device shown in the Sexton patent the degree of relative rotational movement of the annular body of mercury with respect to the casing forming the annular chamber in which the mercury is contained is limited to the degree of expansion and contraction of the Sylphons. When the annular body of mer cury is suddenly stopped in its tendency to overrun the casing due to the rotative deceleration of the axle-driven casing at a high rate, there may be a tendency for the pressure exerted on the Sylphons to pulsate thereby causing a vibratory movement of the switch lever and a possible consequent fluttering of the switches between open and closed positions.

It is accordingly a further object of my invention to provide a fluid type inertia device comprising an arrangement for permitting the an= nular body of mercury to continue rotation at a certain limited rate of change of speed, either acceleration or deceleration, whenever the shaft or axle changes its speed at exceptionally high rates, in order to enable the continued application of an inertia force to a switch lever to maintain it positively in a closed position until such time as the rotational speeds of the annular mercury column and the rotational speed of the axle or shaft are again synchronized.

In the control of the brakes to prevent sliding of the whels, it is essential that the reduction of brake cylinder pressure be maintained after the wheel begins to slip in order to insure the return of the wheel to a speed corresponding to car speed without decelerating to a locked condition. It is thus imperative to maintain a control switch of a fluid type inertia device positively in its closed position in order to insure the continued reduction of brake cylinder pressure. My improved fluid type inertia device is operative to initiate a reduction of brake cylinder pressure whenever slipping of the car wheel is initiated and inherently causes such reduction of brake cylinder pressure to be positively continued during the slipping cycle until the slipping wheel has been restored substantially to car speed.

The above objects, and other objects of my in vention, which will be made apparent hereinafter, are attained by several embodiments of my invention subsequently to be described and shown in the accompanying drawings, wherein Fig. 1 is a diagrammatic view showing one embodiment of a fiuid type inertia device as applied to the end of a car wheel axle and functioning in a fluid pressure brake control system to control the brakes associated with the car wheel in a manner to prevent sliding thereof,

Fig. 2 is an enlarged sectional view showing, in detail, the construction of a centering spring mechanism for the switch operating lever shown in Fig. 1,

Fig. 3 is a sectional view, taken on the line 3-3 of Fig. 1, showing further details of construction of the device shown in Fig. 1,

Fig. 4 and Fig. 5 are enlarged views, showing separated and assembled relation of parts respectively of the mechanism for transmitting the inertia forces of the annular mercury column to a switch lever.

Fig. 6 is a view, taken on the line 66 of Fig. 4, showing further details of the parts shown in Fig. 4,

Fig. '7 is a fragmental sectional view, taken on the line 1--1 of Fig. 5, showing details of construction of the diaphragm follower of Fig. 5,

Fig. 8 is a sectional view of a second embodiment of my invention,

Fig. 9 is a fragmental sectional view taken substantially on the line 9-9 of Fig. 8,

' Fig. 10 is an enlarged sectional view, taken on the line ll-IU of Fig. 8,

Fig. 11 is an enlarged fragmental view showing a modification of the embodiment shown in Fig. 8,

Fig. 12 is a fragmental side view partly in section taken substantially on the line I2|2 of Fig. 11, with the end of the tubular member removed for clarity.

' Fig. 13 is an enlarged sectional view, taken on the line l'3--l3 of Fig. 11,

Fig. 14 is a fragmental view showing a second modification of the embodiment shown in Fig. 8,

Fig. 15 is a fragmental plan view of the modification shown in Fig. 14,

Fig. 16 is a fragmental side elevational view of the embodiment shown in Figs. 14 and 15, and Fig. 17 is a fragmental view taken on the line iT-H of Fig. 16.

Description of embodiment shown in Figures 1 to 7 Referring to Fig. l, the embodiment of my fluid type inertia device shown is illustrated as associated with the axle l I of a car wheel l2, the axle being rotatably supported in the usual manner, as by roller bearings IS, in a journal casing I l. The pedestal jaws l5 of the side frame of a railway car truck engage in the usual side grooves in the journal casing for limited vertical movement relative thereto.

Substituted for the usual end cover secured to the outer open end of the journal casing I4 is a casing member [6, screws I1 being provided for securing the casing member 16 to the journal casing l4 in the same manner as the usual end cover. The outer open end of the casing member I6 is closed by an end cover l8 that is secured to the rim of the casing member I6 as by a plurality of screws I9. The casing member 16 and the end cover I8 accordingly provide a chamber 2| within which the fluid type inertia device comprising my invention is contained.

The fluid type inertia device comprises two semi-circular tubular members or pipes 22a and 221), preferably of circular cross-section, disposed in complemental circular form with the adjacent lower ends secured, as by welding, in a lower supporting bracket 23 and with the adjacent upper ends secured, as by welding, a diaphragm casing member 24. The bracket member 23 and the diaphragm casing member 24 are provided with suitable flanges that are secured, as by a plurality of bolts 25 to corresponding ones of two oppositely extending arms 26 of supporting spider member 21. Spider member 21 has a central circular hub portion 28 which is secured to the outer end of the axle H as by a plurality of screws 29. The hub portion 28 has a bore 3| in which the outer end of axle H fits closely, thereby accurately positioning the spider member 21 in coaxial alignment with the axle and at the same time reducing the shearing stresses on the screws 29.

Casing It has an annular flange Kid, in central opening of which is secured an oil retainer ring 23 that surrounds the hub portion 28 of member 2'! to prevent oil from the axle journal entering chamber H.

The disposition of the tubular members 22a and 22b is such as to form an annular passage rotatable coaxially to the axle ii, that is, with the center of curvature of the annular passage in coincidence with and intersected by the axis of rotation of the axle H.

A through passage or bore 33, having a crosssection corresponding to that of the tubular members 22a and 22b, is provided in bracket 23. The adjacent lower ends of the tubular members fit tightly in the opposite open ends of the passage 33 and are welded to the bracket member 23.

In order to provide a means for filling the tubes 22a and 22b with mercury or other suitable liquid of high specific gravity, the bracket member 23 has a threaded port opening out of the passage 33, a screw plug being provided for closing the port after filling the tubes.

Due to the fact that the coefficient of thermal expansion of mercury is relatively high compared to the thermal coefficient of expansion of steel, nickel, or other metal of which the tubular memthe . brs 22a and 221) may be made, it is necessary to provide means for enabling the tubes to remain filled at all times and yet prevent the bursting of the tubes and the consequent loss of the mercury due to increase of ambient temperature. This is especially necessary where the device is subject to large variations in ambient temperature, as in railway service, where the climatic temperature may vary from sub-zero (Fahrenheit) to temperatures of one-hundred degrees or more. Accordingly, I provide an expansible and contractable chamber, in the form of a flexible bellows or Sylphon 34, one end of which is attached as by welding to the bracket member 23 and the other end of which is closed by a disk 36 welded. thereto, the interior of the Sylphon being connected to the passage 33 through a port 3?.

A loading spring 38 is interposed between the disk 36 on the end of the Sylphon and one leg of an angle bracket 39 that is adjustably secured, as by a screw 42, to the adjacent arm 26 of the spider member 27. The arm 26 and the leg of the bracket 39 are provided with cooperating serrated surfaces 4| for locking the bracket in a fixed position to which adjusted. The loading spring is so designed and adjusted as to per mit the expansion of the Sylphon 34 in response to thermal expansion of the mercury and at the same time prevent the expansion of the Sylphon in response to inertia or momentum forces of the mercury.

The diaphragm casing member 24 comprises two complemental parts or casing members 24a and 24b, generally similar in appearance to the cooperating parts of hose couplings of fluid pressure brake apparatus on railway cars. The two casing members are substantially identical, the member 240. differing from the member 2% in having integrally formed flanges whereby to secure the casing member 24a to the arm 26 of the spider member 21.

Referring particularly to Figs. 4 and 5, each casing member has an end portion into which the corresponding end of the tubular member 22a or 2212 is received and suitably secured as by brazing or welding. Formed within each of the members 24a and 24b is a passage 48 opening at one end into the tubular member 22a or 221) and terminating at the opposite end within an annular rib seat 49 at the contact face of the member, on which seat a by-pass check valve carried by the other member is adapted to seat.

The two casing members 24a and. 24b are provided with suitable cooperating lugs 52 having holes 53 that register when the two members are fitted together. Suitable securing bolts 54 extending through the holes in the lugs 52 hold the two members together.

Formed in the contact face of each of casing members 24a and 24b and surrounding the annular rib 49 is a suitable annular aligning groove 55 for receiving a cooperating annular aligning rib 56 on the cooperating contact face of the complemental member 2411 or 24?).

Concentrically surrounding the annular aligning rib 58 on each of the members 24a and 24b is an annular sealing rib 5! which engages the smooth contact face of the complemental mem ber when the two members are clamped together.

The location of the lugs 52 is such as to cause the bolts 54 to eXert a clamping force on diametrically opposite sides of the sealing rib 51 and closely adjacent thereto whereby to insure a tight metal-to-metal seal at the contact faces of the members 24a and 24b.

Each by-pass check valve 5| is urged into seated relation on the annular rib seat 49 of the complemental member 24a or 24b by a coil type loading spring 58 which is interposed between the valve 5| and the inner end of an adjusting screw 59. Each valve 5| has a stem 6| that is slidably supported in a bore 62 in the end of the corresponding adjusting screw 59.

Each adjusting screw 59 extends to the exterior of the corresponding member 24a or 24?) and is provided with a suitable lock nut 53 and cap nut 64. The cap nut seals on an annular sealing face formed on the outer surface of the casing member to guard against the possibility of leakage of mercury along the adjusting screw 59.

It will be apparent from Fig. 5 that the relation of the bypass check valves 5| and the passages 48 in the two members 24a and 24b is such that when the check valves are unseated, mercury is permitted to flow from the passage 48 in one of the members 24a or 24b to the passage 48 in the other member, thereby also providing communication from the upper end of one of the tubular members 22a. or 221) to the corresponding end of the other tubular member. It will at the same time be apparent that the check valve 5| carried by the member 2411 is unseated only to permit the flow of mercury circularly in the tubes 22a and 22b in one direction whereas the check valve 5| carried by the member 24b is unseated only to permit the circular flow of mercury in the tubes 22a and 22b in the opposite direction.

The portion of the casing member between the two contact faces of the members 24a and 24b is formed to provide a circular bore 66 when the two members are in assembled relation. Each of the members 2411 and 24b is provided with a circular flexible diaphragm 61 having a peripheral ring of metal which is in turn welded to the casing member 240. or 242) at the base of the bore 66. The diaphragms 6'1, which may be of suitable rubber material or of suitable thin sheet metal, are dish-shaped and the flat portions of the diaphragm are held against an annular rib 58 surrounding a relatively large passage or bore 69 opening out of the passage 48 of the corresponding member 24a or 242). The diaphragms 61 are accordingly subject to the pressure of the mercury in the passages 48 transmitted to the inner face of the diaphragms through the passages 69.

The manner in which the diaphragms 61 are secured to the casing members 240. and 24b in engagement with the annular rib 68 is such as to prevent sharp bends in the diaphragm and thus to minimize the bending stresses due to fiexure of the diaphragm.

In view of the fact that mercury has a corrosive effect on certain materials or metals, it will be understood that all of the various elements, thus far described or hereinafter to be described, with'which th mercury comes in contact must be of a material not corroded by mercury. Thus, various metals such as steel, nickel, or alloys thereof are not corroded by mercury. Certain plastics or molded materials such as Bakelite, Micarta or rubber are likewise not corroded by mercury.

Conforming closely to the diameter of the bore 66 and slidably shiftable therein is a diaphragm follower 7| of suflicient width to conform closely to the normal spacing between the diaphragms 61 so as to be shiftable in opposite directions in the bore 99 in response to pressures exerted on the diaphragms in opposite directions.

The diaphragm follower TI is preferably of a molded material, such as Bakelite or Micarta and is formed preferably in two complemental sections secured together in abutting relation by means of a plurality of rivets I3.

Formed concentrically to the axis of the follower II on the inside face of each of the complemental portions is a circular boss I4 in which a suitable metallic member is embedded for providing an outer metallic contact face for the boss. The two bosses T4 of the complemental portions of the follower II extend toward each other and the ends thereof are normally spaced apart a certain distance for receiving therebetween the curve-sided contact head I6 of a switch operating arm or lever 11.

The periphery of the follower II has a suitable opening 18 which is in radial alignment with a corresponding opening 79 (see Figs. 4 and 6) formed at the inner side of the two members 24a and 2410 when the members are in assembled relation. Formed at the edge of the opening 79 on each of the members 24a and 24b is a pivot lug 8|, the two lugs being aligned when the two members 29a and 242) are assembled and having aligned holes 82 for receiving a pivot pin 83 on which the switch lever TI is pivoted. The portion of the switch lever 11 on one side of the pivot pin 83 extends radially outward through the opening 19 in casing members 2411 and 24b and the opening 79 in the follower 1| and has the contact head I9 secured or formed at the end thereof. The portion of the switch lever 77 at the opposite side or" the pivot pin 83 extends radially inward and is provided with a forked end which straddles a switch operating plunger 89 between two shoulders formed by a portion of reduced diameter on the plunger. (See Fig. 1.)

Associated with the switch lever IT at a point between the pivot pin 83 and the plunger 86 are two centering spring devices 81 (Fig. 1), adjustably secured as by screws 88 to a bracket 89 that is in turn secured as by screws 9| to the adjacent arm 29 of the spider member 21.

As shown in Fig. 2, each of the centering spring devices 8'! comprises a small cylinder 92 having an opening 93 at one end through which a contact member 94 extends. The contact member 94 has a peripheral flange which engages an inwardly extending flange on the end of the cylinder 92 to limit the outward movement of the contact member 94. A loading spring 95 of the coil type is contained in the cylinder 92 in interposed relation between the contact member 94 and an adjusting screw 95. Screw 96 is looked. as by a lock nut 91, in a threaded opening provided in a cap screw 98 closing the end of the cylinder 92 opposite the opening 93.

Referring to Fig. 1, it will be seen that one of the devices 8'! is secured to the bracket 89 on one side of the switch lever 11 and the other of the two devices 9! is secured to the bracket 89 on the opposite side of the switch lever IT.

The cylinders 92 are adjustably secured to the bracket by means of the screws 88 so that the contact members 94 just engage opposite faces of the switch lever 17. The switch lever 11 is thus yieldingly held in a normal centered position determining the normal position of the switch operating plunger 96. The tension of the loading springs 95 may be adjusted by means of the screws 99 to provide any desired resistance to movement of the switch lever 17 out of its centered position and a corresponding force eifective to restore the switch lever 71 to its centered position. When employed to control the brakes associated with car wheels, the centering springs are so adjusted as to prevent sufficient pivotal movement of switch lever 'I'I out of its centered position to operate switch contacts, presently described, unless the rate of acceleration or deceleration of the axle II exceeds a slipping rate.

The switch operating plunger 86 is slidably supported in a central boss 99 on the end cover I8 and in a cup-shaped collar I9I attached, as by screws I92, to the inner face of the end cover I8 in coaxial alignment with the axis of rotation of the axle II. The length of the switch lever I7 is such that the forked end thereof remains in cooperating engagement with the plunger 86 as the axle II and spider member 21 rotate so as to be constantly effective to slidabl move the plunger 86 in opposite axial directions depending upon the direction in which the switch lever TI is pivoted on the pivot pin 83.

An annular packing or oil retainer ring I93 may be provided in the collar I9! for preventing oil from the axle journal that may possibly enter the chamber 2| within the casing I9 from traveling along the plunger 89 to the exterior of the end cover I8 and thereby contaminating the switch contacts mounted on the outer face of the end cover I 8 in the manner presently to be described.

For a reason which will be presently explained, it is desirable to prevent the rotary movement of the switch plunger 86. A pin I94 fitted diametrically in the plunger 89 and engaging at its opposite ends in two spaced slots I95 formed on the collar I9I serves to prevent the rotation of the plunger 86.

The plunger 89 is provided with a rounded tip 960., of insulating material, which tip engages a flexible contact finger I96. The flexible contact finger I99 is embedded in a suitable insulatin base I9! having a securing bolt I98 embedded therein and provided with a suitable nut I99 and lock nut II9 for securing the base I91 to a projecting lug III on the outer face of the end cover I9 at one side of the plunger 89. The lu II I is provided with a groove I I2 having tapered sides for receiving a cooperating tongue formed on the insulating base I91 whereby to aid in fixing the position of the flexible contact member I96 while permitting axial adjustment of the position thereof. A slot I I3 is provided in the lug II I for permitting the movement of the securing bolt I98 with the base I97.

Two relatively short contact fingers H5 and H6 respectively are carried by insulating bases I91 having securing bolts I98 for attaching the contact fingers to a projecting lug II8 on the diametrically opposite side of the plunger 86 relative to the lug III. The lug H8 is provided with a groove having tapered sides for receiving a correspondingly tapered tongue on the bases I91 of the contact fingers H5 and I I9, as well as a slot H3 through which the securing bolts I98 extend. The tongue and groove relation of the lug H8 and bases I91 enables axial adjustment and alignment of the contact fingers I I5 and H9 and provides support for the bases additional to the bolts I98.

The two contact fingers I I5 and I I6 are secured in spaced relation to each other in such manner that the tip end of the contact finger I99 is substantially midway therebetween.

The flexible contact finger I96 has an inherent initial bias in the direction of the contact finger H3 but is flexed or bent to a normal position midway between the two contact fingers I I5 and I iii in the normal position of the plunger 86.

The plunger 86 is restrained from rotation by the pin I94 in order to prevent the wear of the tip end of plunger and the flexible contact finger H38 at the point of contact thereof, which would result if the plunger were permitted to rotate.

If the plunger 86 shifts in the left-hand direction a sufiicient amount in response to the pivotal movement of the switch lever H, the tip end of the flexible contact finger I96 engages contact finger H5. If the plunger 85 is shifted axially inwardly toward the axle a sufficient amount, the inherent bias in the flexible contact finger I96 causes it to follow the plunger 86 until it engages the contact finger I I6. It will thus be seen that upon movement of the plunger 86 a sufficient amount axially in either direction, the contact finger I06 engages either the contact finger I I5 or the contact finger I I6.

While I have shown the contact fingers I66, I I5 and E It as extending vertically, it will be apparent that they may be positioned horizontally if desired.

A cover member I2I of relatively light-weight sheet metal is attached as by screws I22 to the outer face of the end cover I8 to enclose the switch contact fingers I05, H5, and I56.

A lead wire I23 having suitable insulation is soldered or otherwise suitably secured to the base end of the fiexible contact finger I06 and extends through a suitable insulated opening in the cover I21 to the exterior thereof.

The two contact fingers H5 and IIE are connected to a common wire I24 having suitable insulation and extending through the opening in the cover I2I to the exterior thereof.

The wires I23 and I 24 may lead to any desired control circuit. As shown, the wires I23 and I24 constitute a part of a control circuit for a magnet valve device I25 controlling the release of fluid under pressure from a brake cylinder I26 for operating the usual brakes associated with the car wheel I2.

For simplicity, a simple brake control apparatus of the straight-air type is shown in Fig. 1 for the purpose of illustrating the manner in which the magnet valve device I25 controls the pressure of the fluid in the brake cylinder I26. It will be understood, however, that the magnet valve I25 and the fluid pressure brake control apparatus shown and presently to be described is merely illustrative of conventional equipment or any suitable brake control equipment employed.

As shown, the brake control apparatus comprises a control pipe I 27 which is normally vented to atmosphere and which is charged with fluid at a different pressure from a reservoir I28 by means of a suitable brake valve I29 of the well-known self-lapping type. With the brake valve handle I29a in its brake release position, the control pipe I27 is vented to atmosphere through an exhaust port and pipe I3I at the brake valve. When the brake valve handle I29a is displaced into its application zone, the pressure established in the pipe I2'l is substantially proportionalto the degree of displacement of the brake valve handle l23a out of its brake release position. The brake valve I29 has, moreover, a pressure-maintaining characteristic so that if the pressure in the pipe I21 tends to reduce for any reason, such as leakage, fluid under pressure is automatically supplied to the pipe I27 to maintain a pressure therein corresponding to the position of the brake valve handle I29a.

The brake cylinder I26 is connected to the control pipe I2'I through a branch pipe I32 in which the magnet valve I25 is interposed. The magnet valve I25 is of a standard type having a double-beat valve I33 which is normally urged to an upper seated position by a coil spring I34 and actuated to a lower seated position in response to energization of the magnet Winding I35 of the magnet valve.

In its upper seated position, communication through the branch pipe I32 from the control pipe I21 to the brake cylinder I26 is established. Thus, the pressure of the fluid in the brake cylinder corresponds to the pressure in the control pipe I21 as long as the magnet winding I35 of the magnet valve remains deenergized.

In its lower seated position, the valve I33 of the magnet valve I25 closes communication through the branch pipe I32 and establishes a venting communication through which fluid under pressure is rapidly released from the brake cylinders through an exhaust port I33. Thus, when the magnet winding I35 is energized, fluid under pressure is vented from the brake cylinder I25.

A pressure operated switch I3! is connected to the control pipe I21 and is of any suitable snapacting type responsive to variations of the pressure in the pipe and below a certain critical pressure, such as five pounds per square inch. The contacts of the switch I31 are in their open position when the pressure in the pipe I21 reduces below five pounds per square inch and are actuated to their closed position whenever and so long as the pressure in the pipe I21 exceeds five pounds per square inch.

The lead wire I24 is connected to one terminal of the magnet winding I35 of the magnet valve with the contacts of the pressure switch I3 1 interposed in series relation therein. The lead wire I23 is connected to the opposite terminal of the magnet winding I35 of the magnet valve with a suitable source of direct current, such as a storage battery I38, included in series relation therein. It will thus be seen that, assuming the pressure switch I31 to be closed, the engagement of the contact finger I08 with either of the contact fingers H5 or IIB completes the circuit for causing energization of the magnet winding I35 of the magnet valve I25.

Operation of embodiment shown in Figs. 1 to 7 Let it be assumed that a railway car having the wheel and axle assembly shown in Fig. 1 is traveling under power and that the operator desires to apply the brakes to bring the car to a stop. In such case, the operator first shuts off the propulsion power and then operates the brake valve handle I29w into its application zone a desired distance to cause fluid under pressure to be supplied to the brake cylinder I25, in the manner previously described, to effect application of the brakes on the wheel I2.

It will be understood that while I have shown only one wheel and axle unit and specific brake control equipment therefor, each wheel and axle assembly on the car is provided with a fluid type inertia device similar to that shown in Fig. l and that the operation of the brake valve I29 controls the application and release of the brakes on all of the wheel and axle assemblies of the car or the train.

Let it be further assumed that when the brakes are applied on the Wheel l2 shown in Fig. 1, the wheel begins to slip. For purposes of illustration, let it be assumed also that the axle II is rotating in a clockwise direction as seen in Fig. 3. It will thus be apparent that, due to the rotative deceleration of the axle H, the mercury in the tubes 22a and 22b acts as a fluid fly wheel tending to rotate at an undiminished speed since the friction of the mercury within the tubes is relatively negligible. The momentum or the force of inertia of the annular column of mercury accordingly causes a pressure to be exerted on the diaphragm 61 secured in the easing member 24a, which pressure is effective to rock the switch lever 11 on the pivot pin 83 in a counterclockwise direction as seen in Fig. 1. In this connection it will be noted that the centrifugal forces of the mercury on the two diaphragms 61 are equal and opposite, thereby rendering the follower II and switch lever ll movable without opposition by centrifugal forces.

As long as the rate of rotative deceleration of the axle is less than a certain rate, such as six miles per hour per second, the momentum force exerted by the mercury on the diaphragm 61 is insuflicient to cause enough displacement of the switch lever TI and consequent inward shifting of the switch plunger 86 to cause engagement of the flexible contact finger I06 with the contact finger H6. However, when the wheel l2 fixed to the axle begins to slip, the axle rotatively decelerates at a rate far in excess of six miles per hour per second. In such case, therefore, the force of momentum exerted by the mercury in the passage 48 of casing member 240. on the diaphragm 61 causes sufficient outward flexing of the diaphragm to cause the flexible contact finger I06 to engage the contact finger H6.

The engagement of the contact fingers I05 and H6 accordingly completes the circuit for energizing the magnet winding I35 of the magnet valve |25 which accordingly operates to cause a rapid reduction of the pressure in the brake cylinder [26.

The loading springs 58 for the by-pass check valves 5| are so designed and are so adjusted by the adjusting screws 59 as to maintain the check valves seated unless the force of momentum of the mercury acting on the diaphragms 61 is suflicient to cause engagement of the contact finger I06 with the contact finger H6 (or with the contact finger II5).

Assuming that the engagement of the contact finger I06 with the contact finger H6 or H5 is effected in response to the rotative deceleration of the axle at a rate between five and six miles per hour per second, the check valves 5| are thus unseated in response to a somewhat higher rate of rotative deceleration of the wheels and. axle of approximately six miles per hour per second.

Thus, substantially at the time that the contact finger I06 engages the contact finger IIB, the particular one of the check valves 5| effective for the direction of rotation of the annular mercury column is unseated, thereby permitting the mercury to flow therepast into the passage 48 of the casing member 241) and thence into the tube member 22b. The degree to which the check valve 5| is unseated is substantially proportional to the pressure exerted by the mercury. Accordingly, the check valve 5| automatically regulates the flow of mercury therepast so as to regulate the rate of rotative deceleration of the annular mercury column to a rate of approximately six miles per hour per second, this rate of rotative deceleration of the annular mercury column being suflicient to maintain adequate pressure by the mercury on the diaphragm 61 to insure the continued displacement of the diaphragm 61 and consequent engagement of the switch, contact fingers I06 and H6.

The wheels and axle, it will be understood, rotatively decelerate at a rate which may attain, at times, a rate as high as one hundred miles per hour per second, but due to the automatic regulation of the braking effect on the rotating annular mercury column exerted by the effective check valve 5 I, the annular mercury column continues to rotate at a speed higher than the rotational speed of the wheel and axle When the degree of application of brakes associated with the wheel 12 and axle II is sufficiently reduced in response to the energization of the magnet winding of the magnet valve I25, the wheel promptly ceases to decelerate and begins to accelerate back toward a speed corresponding to car speed at an abnormally rapid rate of the same order of magnitude as the slipping rate of deceleration of the wheel. However, due to the fact that the annular mercury column is rotating at an instantaneously higher speed than the wheels and axle, although it is being decelerated at a substantially uniform rate of six miles per hour per second, the force of momentum of the mercury column on the diaphragm is maintained and consequently the switch lever 11 remains displaced so as to cause the contact fingers I06 and H6 to remain engaged not merely during deceleration of the wheel at a rate exceeding six miles per hour per second but also during the acceleration of the slipping wheel back toward a speed corresponding to car speed.

When the slipping wheel and axle are restored in speed substantially to the rotational speed of the annular mercury column, the force of momentum of the mercury acting on the diaphragm 61 and check valve 5| is reduced substantially to zero because instantaneously no braking effect is exerted on the annular mercury column.

The diaphragm follower H and switch lever 11 are thus restored to their normal centered position partly because of the resiliency of the diaphragms 61 and partly because of the action of the centering spring device 81 previously yieldingly compressed in response to the displacement of the switch lever I1. As previously explained, the centrifugal forces of the mercury acting on the two diaphragms 61 are balanced and therefore centrifugal force does not interfere with the restoration of the follower II to its normal centered position.

Due to the fact that the annular mercury column has decelerated at a higher rate (six miles per hour per second) than the normal rate of retardation of the car (maximum three miles per hour per second), the annular mercury column is instantaneously rotating at a speed less than the actual speed of rotation corresponding to the speed of the car at the time that the slipping wheel and axle are restored to the speed of the annular mercury column. If, therefore, the axle and wheel continue to accelerate at a rate exceeding approximately six miles per hour per second sufficient to cause unseating of the check valve 5| opposite to that unseated during the deceleration of the axle, such check valve may be momentarily unseated and the switch lever correspondingly shifted in the opposite direction momentarily. This momentary displacement of the switch lever at this time may result in the momentary engagement of the contact finger I 06 with the contact finger II5. However, due to the fact that the annular mercury column is almost instantaneously accelerated to the speed of the wheel and axle the switch lever TI is promptly restored to its normal centered position.

For all practical purposes, therefore, it may be said that in its operation, my fluid type inertia device initiates operation of the switch contacts to their closed position whenever the rate of rotative deceleration of the wheel and axle exceeds a certain rate, which may be taken as a rate occurring only when the slipping of the wheel and axle occurs, and positively maintains the switch contacts in their closed positions thereafter inherently and automatically until such time as the slipping wheels and axle are restored substantially to a rotational speed corresponding to the car speed. The possible momentary operation of the switch contact to a closed position at the conclusion of the slipping cycle may for practical purposes be neglected since it occurs in a minute interval of time of the order of a tenth of a second.

The restoration of the switch lever TI to its normal centered position in the manner previously described and the consequent disengagement of the contact finger I06 from the contact finger H6 interrupts the circuit for energizing the magnet winding of the magnet Valve device I25. The reduction of the pressure in the brake cylinder I26 is thus terminated and the resupply of fluid under pressure thereto effected in response to the restoration of the magnet valve device I25 to its normal condition.

It is desirable not to reapply the brakes on a slipping wheel until it has been fully restored to a speed corresponding to car speed. This is so because if the degree of application of the brakes is increased sufiiciently while a slipping wheel is rotating at a relatively low speed, the wheel may become locked and therefore slide. My fluid type inertia device accordingly functions inherently to hold off or inhibit the reapplication of the brakes on a slipping wheel until it has been restored substantially to a speed corresponding to car speed, thereby eliminating automatically the possibility of sliding of the wheels due to a premature reapplication of the brakes.

Should the wheel I2 again begin to slip upon reapplication of the brakes caused by the resupply of fluid under pressure to the brake cylinder I26, the inertia device again functions to cause operation of the magnet valve device I25 to again reduce the pressure in the brake cylinder I26, thereby causing the slipping wheel to again be restored to a speed corresponding to car speed. Thus, at no time during a brake application are the wheels permitted to become locked and slide.

When the car comes to a complete stop in response to the application of the brakes, the switch lever 71 is always restored to its normal centered position because of the complete dissipation of any inertia forces on the annular mercury column in the tubes 22a and 22b. Accordingly, the magnet winding of the magnet valve I25 is always deenergized when the car comes to a stop. It is thus possible for the operator to cause variation of the pressure in the brake cylinder I23 to any desired degree, to hold the car on any grade encountered in service, when the car stops completely.

If the operator desires to again start the car, he may do so after first restoring the brake valve handle I29a to its brake release position, thereby causing fluid under pressure to be vented from the brake cylinder I26 and control pipe I2! to atmosphere. When the pressure in the con trol pipe I21 reduces below five pounds per square inch, the pressure switch I3"! is restored to its open position, thereby preventing possible energization of the magnet winding I35 of the magnet valve device I25 should the wheel I2 accelerate too rapidly in response to the application of propulsion torque thereto.

While I have not indicated or shown any equipment for applying propulsion directly to the axle II, it is assumed that such may be the case. Accordingly, if the propulsion torque applied to the axle I I is sufiicient to exceed the limit of adhesion between the wheel and the rail on which it rolls, the inertia device will respond in a manner similar to that occurring during deceleration of the axle II.

In the case of the rotative acceleration of the axle I I, however, assuming the same direction of rotation as in the previous instance, the inertia force of the annular mercury column in the tubes 22a and 22b is now active on the diaphragm 61 in the casing member 2% because the column tends to lag behind the axle I i. In such case, therefore, the switch lever 11 is rocked on its pivot pin 83 in a clockwise direction, as seen in Fig. 1, thereby causing outward movement of the plunger 86 to cause the contact finger I06 to engage the contact finger H5.

With the pressure switch I31 in open position, however, energization of the magnet winding of the magnet valve I25 cannot be effected, thereby preventing the unnecessary consumption of current from the storage battery I38.

Let it now be assumed that the operator re verses the propulsion motors or that the car is so connected in a train that the wheel I2 and axle I! rotate in the opposite direction to that previously assumed, that is, in a counterclockwise direction as seen in Fig. 3.

If, upon application of the brakes in such case, the wheel I2 begins to slip, it will be apparent that the momentum force of the fiuid fly wheel or annular mercury column is now exerted on the diaphragm 61 in the casing member 241), just as in the case of the acceleration of the axle ll when rotating in clockwise direction. The switch lever 71 is accordingly shifted pivotally on its pin 83 so as to cause outward movement of the plunger 86 and engagement of the contact finger I06 with the contact finger II5. With the pressure switch I3! in its closed position, due to the fact that the pressure is established in the control pipe I21 during a brake application, the magnet winding of the magnet valve I25 is thus again energized to effect a reduction of the pressure in the brake cylinder I26.

In this case, the by-pass check valve 5! at the end of passage 48 in the casing member 2422 is unseated, following the engagement of the contact finger I06 with the contact finger H5, to permit the continuous rotation or circular movement of the mercury in the tubes 22a and 221) at a speed reducing at the rate of approximately six miles per hour per second.

Switch lever H is accordingly maintained displaced in a clockwise direction so as to maintain the contact finger I06 in engagement with the contact I I until such time as the slipping wheels are restored substantially to a rotational speed corresponding to the rotational speed of the annular mercury column.

After the wheels are restored substantially to car speed, therefore, the switch lever 11 is correspondingly restored to its normal centered position, thereby causing restoration of the contact finger I06 to its centered position disengaging the contact finger H5. The magnet winding of the magnet valve I25 is thus deenergized, thereby terminating the reduction of the pressure in the brake cylinder and initiating the resupply of fluid under pressure thereto to effect the reapplication of the brakes on the wheels.

It will thus be seen that my fluid type inertia device functions automatically for either direction of rotation of the wheels and wheel axle I I.

Embodiment shown in Figures 8, 9, and 10 Referring to Figs. 8, 9, and 10, another embodiment of my invention is shown which differs somewhat from the previously described embodiment. Certain parts of the apparatus are identical, or substantially identical, to corresponding parts in the first described embodiment and a description of these parts Will thus not be repeated, it being deemed sufficient to identify such parts by the same reference numerals as previously employed.

Essentially, the embodiment shown in these figures comprises a spider member 21a attached by screws 29 to the end of the axle II in the same manner as the spider member 21 in the first described embodiment. The spider member 21a differs from the member 21 in having-not two--but three radially extending arms 26a projecting outwardly from the central hub portion 28a, the arms being spaced substantially 120 apart, and a short radial lug or arm IIll midway between two of the arms.

The device further comprises two semi-circular tubular members 220 and 22d disposed in complemental alignment in the form of a ring. Two adjacent open ends of the tubular members 220 and 22d are welded in the opposite ends of a passage 33 in a bracket member 23a corresponding to the bracket member 23. The diametrically opposite adjacent ends of the two tubular members 22c and 2201 are welded to the open ends of two Sylphons I45 and the opposite open ends of the Sylphons are Welded to the opposite faces of a floating or shiftable casing member I46 in the manner more fully described presently.

The tubes 22c and 22d are further secured to the spider member 21a by means of brackets I41 surrounding the tubes and attached as by screws I48 to the arms 2611.

An expansion chamber, in the form of a Sylphon 34, is associated with the bracket mem ber 23a in the same manner as in the first described embodiment.

In order to prevent failure of the Sylphons I45 due to the high mechanical stresses exerted thereon as a result of the centrifugal forces of the casing member I46 as well as of the mercury within the tubes 22c and 22d, the casing member I46 has a diametrically extending arm I5I attached to the inner portion thereof, as by welding, which arm is pivoted on a spindle I52 projecting from the hub portion 28a of the spider member coaxially to the axis of rotation of the axle I I. The arm I5I extends beyond the spindle I52 and carries a counter-weight I53 welded or otherwise secured on the end thereof. The counter-weight I53 is of such a. weight as to counterbalance the weight of the arm I5I and of the casing member I46, whereby to provide a substantial dynamic balance of the rotating parts without interfering with the circumferential movement of member I46.

As seen in Fig. 10, the floating casing member I46 is substantially tubular in form and has integrally formed therein two annular axially spaced rib seats I55 and I56. Seated on each annular rib seat I55 and I56 is a corresponding check valve I5'I in the form of a metallic disk, a loading spring I58 acting on each valve in a direction to seat it. The annular rib seats I55 and I56 may be sharpened to a knife edge, if desired, to provide uniform opening and closing pressures therefor.

The loading force of each spring I58 is adjusted by an adjusting screw I59 screwed into the open threaded end of the casing and locked in position by a lock nut I6I. Each end of the casing is provided with an external thread for receiving a cap nut I62 that has a sealing edge that seats on a corresponding contact face I63 on the casing.

The valve seats I55 and I56 are located in a transverse passage I66 in the casing having openings at opposite ends in which the Sylphons I45 are secured. The disposition of the check valves I5! is such that one of the check valves is unseated to permit flow of fluid from one of the tubes 220 or 22d to the other tube in one direc tion while the other of the check valves is unseated to permit the flow of fluid between the tubes in the opposite direction.

The loading springs I58 for the check valves I51 are so designed and are so adjusted as to prevent unseating of the check valves until the inertia or force of momentum of the mercury within the tubes 22c and 22d acting in response to rotative deceleration of the axle II, exceeds a certain value which occurs only when the wheels slip, that is, exceed a certain rate of rotative decelartion such as six miles per hour per second. Accordingly, the casing member I46 is shifted bodily along an arc corresponding in curvature to the radius of curvature of the tubes 22c and 22d in one direction or the other direction depending upon the direction of application of the inertia force or force of momentum of the mercury in the tubes, the Sylphons yieldingly permitting such movement. This arcuate shifting of the casing member I46 is translated to a switch lever Ila having a forked end cooperating with the switch operating plunger 86 in the same manner as in the first described embodiment.

The switch lever 11a is pivoted on a supporting member I65 in the form of a screw attached to the short arm or lug IIIl projecting radially from the hub portion 28a of the spider member 21a in diametrical relation to the one of the arms 26a to which the bracket member 23a is secured. The screw I65 extends through an arcuate slot I66 in the counter-weight arm I 6| which slot permits the necessary pivotal movement of the counter-weight arm in response to the shifting of the casing member I46 A roller I6! is rotatably mounted on the outer end of the switch lever Ila and cooperates with a shallow V-shaped notch I68 formed on one side of the counter-weight arm I5I adjacent the casing I46.

A leaf spring I69, attached at one end to the support I65, bears against the outer end of the switch lever 11a for biasing the switch lever normally to a certain position in which the roller I61 occupies a centered position in the deepest portion of the V-shaped notch I 68. In this position of the switch lever 11a, the plunger 86 is positioned in the same manner as the plunger 86 in Fig. 1, that is, so as to center the contact finger I06 controlled thereby in the normal centered position between the two contact fingers I I6 and II5.

Operation of embodiment shown in Figs. 8, 9, and 10 Let it be assumed that the vehicle having the axle II in Figs. 8, 9, and 10 is traveling in a direction such that the axle is rotating in a clockwise direction as seen in Fig. 8 and that when the operator applies the brakes to the wheels fixed on the axle slipping of the wheels occurs. In such case, the force of momentum of the annular mercury column in the tubes 22c and 22d is exerted on the casing member I46 so as to shift it in the direction of rotation of the mercury column. The Sylphons I45 are respectively expanded and contracted so as to permit the arcuate bodily movement of the casing member I46 and the consequent pivotal movement of the counter-weight arm II on the spindle I52. This movement of the casing member I46 causes a corresponding movement of the roller I61 in the left-hand direction, as seen in Fig. 9, and a consequent pivotal movement of the switch lever 11a in a counterclockwise direction. The switch operating plunger 86 is accordingly shifted in the right-hand direction as seen in Fig. 9 and is thereby effective to permit the contact finger I66 shown in Fig, 1 to engage the contact finger I'I6.

Operation of the magnet valve device I25 is thus eiiected in the same manner as in the first described embodiment to efiect a release of fluid under pressure from the brake cylinder I26 and a consequent restoration of the slipping wheel or wheels back toward a speed corresponding to car speed.

If the motion of the annular mercury column in the tubes 22c and 22d is suddenly stopped without opportunity for the mercury column to continue its rotation at a gradually diminishing speed, the momentum forces exerted on the easing I46 and efiective to maintain the switch lever 11a displaced may vary in such a manner as to produce a vibratory movement of the switch lever 11a and a consequent alternate opening and closing of the switch contacts.

In order to prevent such fluttering of the switch contacts, the check valves I51 in the easing member I46 are unseated in response to the momentum force of the annular mercury column, after the casing I46 is shifted out of its normal centered position a sufiicient amount to effect closure of the switch contacts to permit the continued flow or circulation of the annular mercury column through the casing member I46 in the direction of its rotation. In the assumed instance, that is with the axle rotating in a clockwise direction, it will be seen that the lower check valve I51 in Fig. is unseated to permit the flow of mercury from the left-hand tube 220 to the right-hand tube 22d, the valve I51 being unseated to a degree proportional to the force of momentum of the mercury.

The resistance ofiered to the flow of mercury through the casing member I46 by the check valves I51 is, moreover, effective to cause the force displacing the casing I46 out of its centered position to be maintained. Such continued displacement of easing member I46 is consequently eiiective to maintain the switch arm 11a in its displaced position causing engagement of the contact finger I06 with the contact finger II6.

In this connection, it will be observed that the check valves I51 serve in the same capacity as the by-pass check valves 5| of the first described embodiment, namely, to limit or regulate the rate of deceleration (or acceleration) of the annular mercury column to a value just sufficient to maintain the switch contacts closed.

It will thus be seen that in the same manner as in the first embodiment, the annular mercury column of the present embodiment continues to rotate at a speed that diminishes gradually with respect to the rotational speed of the axle at the time the slipping of the wheels occurred due to the quasi braking action on the mercury column resulting from the restriction of the check valves I51. Thus, until the slipping wheels are restored in speed sufiiciently to approach the speed of rotation of the annular mercury column, the momentum force of the annular mercury column continues to be effective to unseat the check valve I51 for the corresponding direction of rotation. Accordingly when the slipping wheels are restored substantially to car speed again following the reduction in the degree of application of the brakes initiated by operation of the inertia device, the check valve I51 is reseated and the casing member I46 is restored to its normal centered position in response to the resilient action of the Sylphons I45.

With the casing member I46 restored to its normal centered position, the leaf spring I69 is effective to restore the switch lever 11a in a clockwise direction to its normal position wherein the switch operating plunger 86 restores the contact finger I 66 to its centered position between the contacts II 5 and II 6, This is effective, as in the first described embodiment, to terminate further reduction of pressure in the brake cylinder and to initiate resupply of fluid under pressure thereto to cause reapplication of the brakes.

If slipping of the wheels occurs while the wheels and consequently the axle II are rotating in the opposite direction, that is in a counterclockwise direction as seen in Fig. 8, a similar operation occurs except that the upper check valve I51 is now unseated in response to the momentum force of the mercury column in the tubes 22c and 2212 after the casing I46 is displaced in a counterclockwise direction. The switch lever 11a is, however, shifted pivotally in a counterclockwise direction just as for the opposite direction of rotation of the axle, due to the cooperative relation of the roller I61 with the V-notch I68 on the counterweight arm I5I.

It will thus be seen that the device shown in Figs. 8, 9, and 10 operates automatically for either direction of rotation of the axle.

Figures 11, 12, and 13 The embodiment of my invention shown in Figs. 11, 12, and 13 is identical to that shown in Figs. 8, 9, and 10 except for the provision of a modified form of easing member I46a in place of the casing member I46.

The casing member I46a comprises two substantially parallel tubular portions I15 and I16 connected by a short neclg I11 extending trans- VULOCly ucowccu. uLlC uWU uuNLLLcu. LLLCLI-LUUJ-B PUL- tions and joining them substantially midway between the ends thereof.

The tubular portion I16 has a smooth bore I18 open at the opposite ends thereof whereby to re ceive a cylindrical slide valve I19 for operation therein. The slide valve I19 comprises a central imperforate abutment or piston I8I and two annular end pistons I82, one on each side of the central piston I8I and joined to the central piston by tubular stems I 83.

The tubular stems I83 are provided with one or more openings I84 therein whereby to provide open communication between the opposite sides of the annular pistons I82 and thereby balance the fluid pressures, presently described, acting on the pistons.

Th annular cavities I85, surrounding the tubular stems I83 between the central piston 8| and each of the end pistons I82, serve to control communication between two spaced ports I86 and I81 opening into the bore I18.

The port I89 is at one end of a curved passage I 88 that has its opposite end open at one end of the tubular portion I of the casing. The port I 81 is at one end of a curved passage I89 that has its opposite end open at the other end of the tubular portion I15 of the casing.

The tubular members 220 and 2201 are connected to the open ends of the passages I88 and I89 respectively through Sylphons I45 which are suitably secured to the tubular members and the casing member I460 as by welding.

The cylindrical slide valve I19 is normally centered in the bore I18 by centering pins I9I; and in such position of the valve the central imperforate piston I8I seals on an annular shoulder formed between the ports I86 and I81. Each centering pin I 9I is slidably and loosely mounted in a corresponding adjusting screw I92 screwed into a suitably threaded hole in a collar I93 that fits closely in a counter bore I 94 at the outer end of the bore I18.

A coil spring I 95 concentrically surrounds each pin I 9|, in interposed relation between a head I96 at the inner end of each pin I9I and the inner end of the adjusting screw I92 and yieldingly urges the pin I9I into contact with the central piston I8I of the slide valve I19.

The adjusting screws I 92 may be turned in either direction to vary the loading force of the springs I95 on the pins I9I, a lock nut I91 being provided for locking the adjusting screw in position.

The outer end of each of the centering pins I9I has a collar I98 riveted thereon for holding the pin in assembled relation with the screw and preventing movement of the pin in response to the expanding force of the loadin spring I95 beyond a certain point.

The collars I98 carrying the adjusting screws I92 are secured in the casing by means of cap nuts I99. Each cap nut I99 is provided with an inner shoulder having an annular sealing rib 28I that engages the corresponding end of the tubular portion I18 of the casing. This inner shoulder in each cap nut also engages a suitable annular compressible gasket 202 on the outer face of each of the collars I93, whereby the cap nut exerts a force holding the collar in position without interfering with the sealing contact of the rib I on the end of the tubular portion I16 of the casing.

The centering pin loading springs I 95 on opposite sides of the central piston IBI o the S d valve Ila are uilllurlllly tensioneu Dy U19 adjusting screws E92 so as to cause the central piston 8I of the slide valve I19 to be positioned on the annular shoulder between the ports I and I81. Moreover, the loading force of the springs I is so adjusted as to prevent the movement of the slide valve I19 in the bore, in either direction from the normal central position, except in response to a predetermined force of momentum of the mercury in the tubes 22c and 22d exerted on opposite sides of the central piston I8I. Such predetermined momentum force of the mercury occurs only when the wheels rotatively decelerate at a rate exceeding a certain slipping rate, such as six miles per hour per second.

Sylphcns M5 are so designed that the momentum force of the mercury in the tubes acting on the casing member I 46a is sufiicient to shift it bodily in one direction or the other only when the momentum force exceeds a certain value occurring in response to the rotative deceleration of the wheels at a rate exceeding a certain slipping rate, such as a rate between five and six miles per hour per second.

In a manner similar to the casing member I85 of the previously described embodiment, the casing member MM is provided with a counterweight arm Lila attached, as by welding, to the tubular portion I15 of the casing and pivoted on a spindle I52 on the hub portion of a spider member 21a in the same manner as in the previous embodiment.

In a manner similar to the counterweight arm I 5I the counterweight arm I5 id has a shallow V- shaped notch I580, formed therein at a point adjacent the tubular portion I15 of the casing.

A roller I61 rotatably mounted on the outer end of a switch lever 11c cooperates with the notch 58a, in the same manner as in the previously described embodiment, whereby the bodily shifting of the casing member Idea in either direction from a central position rocks the switch lever in a manner to cause the engagement of the F contact finger I05 with the contact finger IIB shown in Fig. 1.

The switch lever 11a of the present embodiment is pivotally mounted on a support I 65 that extends through an elongated slot IE6 in the counterweight arm I5! a in the same manner as in the previous embodiment; and a biasing spring I89 of the leaf type attached at one end to the support I65 biases the switch lever 11a in a direction to restore the switch lever to its normal position.

In operation, the present embodiment functions similarly to the previously described embodiment having the casing member I 46. Briefly, the momentum of the annular mercury column in the tubes 22c and 22d exerted on the casing member 38a when the wheels begin to slip shifts the casing member in the direction of rotation of the wheels an amount sufiicient to rock the switch lever 11a to cause engagement of the contact finger M6 with the contact finger IIS.

At the same time, the force of momentum of the mercury exerted on the central piston I8I of the slide valve I19 overcomes the resisting force of one of the centering pins Ni and shifts the slide valve in the bore I18 until the end piston I82 engages the collar I83 at the corresponding end of the bore. In this position of the slide valve I19 a corresponding annular cavity I85 establishes communication between the two ports I 86 and I81 thereby establishing communication between the two tubular members 220 and 22d and permitting the mercury to rotatively circulate in the tubes.

The inertia force or momentum of the mercury exerted on the central piston I8I controls the position of the valve I19 so as to regulate the rate of rotative deceleration of the annular mercury column to approximately six miles per hour Thus the momentum force of the rotating annular mercury column is exerted on the casing member M60; continuously during deceleration and subsequent acceleration of the slipping wheel and axle until such time as the slipping wheel and axle have accelerated substantially back to a rota tional speed corresponding to the rotational speed of the annular mercury column, which in turn is somewhat less than a rotational speed corresponding to car speed.

When the speed of rotation of the slipping wheels is restored to that of the annular mercury column, the inertia force of the mercury column on the casing member l46a and on the central piston I8! of the slide valve I79 is reduced to zero. Thus the centering spring I95 previously compressed is effective to restore the slide valve H9 to its normal centered position interrupting the communication between the ports I88 and I81; and at the same time the casing member Mfia is restored to its normal central position due to the resilient character of the Sylphons I45.

The switch lever Ila is thus restored to its normal position in which the contact finger I05 is disengaged from the contact finger I IS.

The engagement and disengagement of the contact fingers I06 and II? is effective to control the magnet valve I25 in exactly the same manner as in the first described embodiment.

It will be apparent that the present embodiment functions inherently for both directions of rotation of the car wheels and car axle. This is the case because the slide valve I19 shifts in one direction from its centered position in response to a suificient momentum force of the annular mercury column when the wheels and aXle are rotating in one direction and in the opposite direction from its centered position in response to the sufiicient momentum force of the annular mercury column when the wheels and axle are rotating in the opposite direction, communication between the ports I86 and I8! and consequently between the two tubular members 220 and 22d being established in either case by one or the other of the annular cavities I85 on opposite sides of the central piston I8I.

Figures 14, 15, 16, and 17 In the previous two embodiments of a fluid type inertia device employing resilient Sylphons whereby to permit limited movement of a casing member in response to the inertia or momentum force of an annular mercury column it is impor tant to design the Sylphons so as to have sufficient mechanical strength to withstand the high stresses caused by the centrifugal force of the mercury. When the rotating annular mercury column is rotated at a relatively high speed, as it is in railway service applications, it may be difficult to design the Sylphons so as to have sufficient mechanical strength to withstand the centrifugal forces exerted thereon and at the same time be sufiiciently flexible and resilient to permit the required movement of the casing member supported between the Sylphons in a manner to actuate switch contacts.

In Figs. 14, 15, 16, and 17, I have accordingly disclosed another arrangement for reducing the but a single turn of tubing.

stresses on the Sylphons due to the centrifugal force of the annular mercury column.

This embodiment is based on the principle that the centrifugal forces of the annular mercury column on the Sylphons will be reduced if the diameter of the tubular members forming the annular passage for containing the mercury column is reduced substantially from the diameter shown in previous embodiments. With a reduction in diameter of the annular passage containing the annular mercury column, the total weight of the mercury is proportionately decreased, thereby proportionately reducing the momentum force of the mercury. It might be possible to retain the same weight of mercury for a smaller diameter annular passage as for a larger diameter annular passage if the cross-sectional area of the smaller diameter annular passage is correspondingly increased. However, I prefer to employ annular tubular members for containing the mercury, of relatively small diameter since they may be more readily formed or bent into circular form.

In order to attain the necessary weight of mercury whereby to attain the required momentum force for operating switch contacts I have provided the form of fluid type inertia device shown in Figs. 14 to 1'7. In this embodiment a plurality of turns of tubing are arranged in re-entrant fashion to form a continuous circulating passage in order to obtain the desired weight of mercury as a result of the increased length of the mercury column incidental to the employment of a plurality of turns instead of I have illustrated the manner in which two turns of tubing may be employed in connection with the Sylphon type of fluid inertia device shown in Figs. 8, 9, and 10, but it will be understood that the multiple-turn arrangement may be employed in connection with any of the forms of fluid type inertia device disclosed.

Referring to Figs. 14, 15, 16, and 17, it will be seen that the embodiment shown is substantially the same as that in Figs. 3, 9, and 10 except that the diameter of the annular passage formed by the tubular members 220 and 22d is much smaller in proportion to the dimensions of the axle and the journal casing than in the case of the embodiment shown in Figs. 8, 9, and 10. For simplicity, however, I have employed the same reference numerals in designating corresponding parts of the present embodiment as employed in the embodiment shown in Figs. 8, 9, and 10 notwithstanding the different sizes or dimensions of the parts in the two embodiments.

Essentially, the embodiment shown in Figs. 14 to 17 differs from that in Figs. 8, 9, and 10, aside from the different dimensions previously mentioned, in the provision of an additional turn of tubing 22m bent or formed as a ring of substan tially the same diameter as that formed by the tubular members 220 and 22d and open at only one point to form two adjacent open ends. The adjacent open ends of the additional tubular member 22a: are welded to a bracket member 232), similar to the bracket member 2311, in axi-- ally spaced relation to the tubular members 220 and 22d.

Instead of a through passage connecting the tubular members 220 and 2211, the bracket memher 231) has crossed non-connected passages 33a and 331) as shown in Fig. 17. The passage 33a connects one open end of the additional tubular member 221: to the end of the tube 2201 whereas tne passage no connects the other open end or the additional tube 22st to the end of the tubular member 220 secured to the bracket member 23b.

The bracket member 23b is provided with two filling ports corresponding to the filling port 45 of the first described embodiment, a filling port being provided for each of the passages 33a and 3312 so as to permit mercury to be poured directly into each of the passages and thereby readily accomplish the filling of the tubes. Screw plugs 46a and 45b are provided as shown in Fig. 17 for respectively closing the two filling openings into the passages 33a and 33b.

Brackets Mia, similar to brackets Ml, are attached to arms 26a and clamped around the tubular members to provide additional support therefor.

The embodiment shown in Figs. 14 and 17 functions in exactly the same manner as does the embodiment shown in Figs. 8, 9, and 10. It is accordingly deemed unnecessary to describe the operation of this embodiment since it will be readily understood from the foregoing description of the operation of the embodiment shown in Figs. 8, 9, and 10.

Summary Summarizing, it will be seen that I have disclosed several embodiments of my invention relating to a fluid type inertia device, all of which embodiments are based on the same operating principle, namely the utilization of the inertia force or momentum of a fluid fly wheel or rotating annular mercury column in a manner to detect or register the rate of deceleration of a rotary element.

All of the embodiments shown also have the common operating principle of permitting the annular mercury column to continue to rotate at a faster speed than the speed of rotation of the braked rotary element, with which it is associated, whereby to insure the continued closure of switch contacts during the major portion of the time the annular mercury column and the rotary element rotate at different speeds. This feature is produced by various forms of spring loaded check valves which are operative to permit the circulatory flow of the annular mercury column While exerting a braking effect thereon so as to reduce the speed thereof at a certain uniform low rate.

One embodiment dispenses entirely with flexible bellows or Sylphons whereas the other embodiments disclosed all employ Sylphons. Those embodiments employing Sylphons are all provided with a pivoted counterweighted arm providing mechanical support for the Sylphons against the centrifugal forces exerted on the Sylphons.

One of the embodiments employs a plurality of successive turns of tubular members connected in re-entrant fashion to provide a continuous circulatory passage for the mercury. This form of the invention enables a smaller and more compact device without effecting any reduction of the momentum forces of mercury attainable, because of the increased length of the mercury column.

The fluid type inertia devices disclosed herein are described in connection with the control of the brakes associated with a railway car wheel or wheels and function to release the brakes on the car wheels in response to the rotative deceleration of the car wheels at a slipping rate, such as a rate corresponding to the retardation of the car at six miles per hour per second.

While not specifically described, it will be apparent that the fluid type inertia devices which I have disclosed herein are also suited for the detection of the rate of acceleration as well as the rate of deceleration of a rotary element. I do not intend any limitation on the scope of my invention, therefore, except as expressed by the terms of the appended claims.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

l. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, means associating the casing means and the body of liquid in a manner to cause rotational movement of the body of liquid with the casing means at the same speed, said means being operatively responsive to the inertia force of the body of liquid set up when the casing means changes its rotational speed at a rate exceeding a certain rate for permitting the body of liquid to rotatively circulate in said chamber at a speed different from that of the casing means thereby to maintain a certain predetermined inertia force of the body of liquid effective as long as the casing means and the body of liquid rotate at difierent speeds, and control means operatively responsive to the inertia force of the liquid in said chamber.

2. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, means associating the casing means and the body of liquid in a manner to cause rotational movement of the body of liquid with the casing means at the same speed, said means being operatively responsive to the inertia force of the body of liquid set up when the casing means changes its rotational speed at a rate exceeding a certain rate for permitting the body of liquid to rotatively circulate in said chamber at a speed difierent from that of the casing means thereby to maintain a certain predetermined inertia force of the body of liquid effective as long as the casing means and the body of liquid rotate at different speeds, and control means operatively responsive to the inertia force of the body of liquid in said chamber exceeding a second certain force less than said certain predetermined force.

3. A fluid type inertia device comprising casing means having an annular chamber in which body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, pressure responsive means subject to the inertia force of the body of liquid set up when the casing means changes its speed of rotation and movable in accordance with the degree of inertia force, control means operated by said pressure responsive means from a normal inactive position to an active position in response to an inertia force of the body of liquid exceeding a certain value, and means normally effective to cause said body of liquid to rotate With the casing means at the same speed and operatively responsive to an inertia force of the body of liquid exceeding a second certain value higher than the first said certain value for establishing communication permitting said body of liquid to rotatively circulate in said annular chamber at a speed different from the speed of rotation of the casing means thereby to maintain said first certain value of inertia force of the body of liquid effective as long as the body of liquid and the casing means rotate at different speeds.

4. A fluid type inertia device for detecting the slipping condition of a vehicle wheel, said device comprising casing means having an annular tubular chamber in which a body of liquid is confined and being rotatable on an axis that intersects the center of curvature of the annular chamber at a speed corresponding to the rotational speed of the vehicle wheel, means assooiating the casing means and the body of liquid in a manner to permit the body of liquid to rotatively circulate in said chamber at a speed different from that of the casing member only while said wheel is slipping, thereby to maintain a predetermined inertia force of the body of liquid continuously effective in one direction during substantially the entire time the wheel is slipping, and control means operated from a normal inactive po-sition to an active position only in response to the maintenance of an inertia force of the body of liquid exceeding said predetermined inertia force.

5. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the cen ter of curvature of the annular chamber, pressure responsive means associated with said casing and shiitable out of a normal position in response to the inertia force of the body of liquid exerted thereon when the casing means changes its speed of rotation, means effective to limit the rate of change of speed of the body of liquid to a certain rate, notwithstanding a change in the rotational speed of the casing means at a rate higher than said certain rate, to thereby cause said body of lLquid to continuously exert an inertia force in one direction effective to maintain said pressure responsive means displaced out of its normal c-sition as long as the body of liquid and the easing means rotate at diiferent speeds, and control means operatively responsive to movement of the pressure responsive means.

6. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, pressure responsive means associated with said casing and shiitable in one direction or the opposite direction out of a normal position thereof in response to the inertia force of the body of liquid exerted thereon when the rotary member changes its speed of rotation, control means operative from a normal position to an operated position in response to a predetermined inertia force exerted on said pressure responsive means, and means effective when the casing means decelerates rotatively at a rate exceeding a certain rate for limiting the rotative deceleration of the body of liquid approximately to said certain rate to thereby cause said predetermined inertia force of the said body of liquid to be continuously eifective to displace said pressure responsive means in one direction out of a normal position as long as the annular body of liquid and the casing means rotate at different speeds.

7. A fluid type inertia device for detecting the slipping condition of a vehicle wheel, said device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber and at a speed corresponding to the rotational speed of the vehicle wheel, pressure responsive means associated with said casing and shiftable in response to the inertia force of the body of liquid exerted thereon when the vehicle wheel rotatively accelerates or decelerates, control means operative by said pressure responsive means from a normal position to an operated position when the inertia force of the body of liquid on the pressure responsive means exceeds a certain value, and means effective when the vehicle wheel decelerates at a rate exceeding a certain rate occurring only when the vehicle wheel slips for limiting the rate of rotative deceleration of the body of liquid to said certain rate to thereby cause said certain value of inertia force of said body of liquid to be continuously exerted on said pressure responsive means, whereby to maintain said control means in its operated position as long as the body of liquid and the casing means rotate at different speeds.

8. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, pressure responsive means associated with said casing means and movably responsive according to the inertia force of the body of liquid exerted thereon when the casing means changes its speed of rotation, valve means operated from a closed position to an open position in response to a predetermined inertia force of the body of liquid to provide communication permitting the rotational movement of the body of liquid relative to said casing means whereby to cause said predetermined inertia force of the body of liquid to be continuously exerted to displace said pressure responsive means in one direction out of its normal position as long as the body of liquid and the casing means rotate at different speeds, and control means operatively responsive to movement of the pressure responsive means.

9. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, pressure responsive means associated with said casing means in a manner to be movably responsive according to the inertia force of the body of liquid exerted thereon when the casing means changes its speed of rotation, normally closed valve means interposed in said annular chamber in a manner to prevent circulatory rotational movement of the body of liquid within said annular chamber and operative to an open position permitting rotational circulatory movement of body of liquid in said annular chamber relative to said casing means, resilient means biasing said valve means to its closed position and yieldable to permit the valve means to be operated to its open position in response to a predetermined inertia force of the body of liquid, and control means operatively responsive to the inertia force of the body of liquid exerted on said pressure responsive means.

10. A fluid type inertia device comprising casmg means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, two movable abutments disposed in spaced relation along a common axis perpendicular to the plane of rotation of said casing means and parallel to the axis of rotation thereof, said movable abutments being so arranged as to be subject respectively to the oppositely directed inertia forces of the body of liquid, a follower interposed between said movable abutments, and shiftable in opposite directions in response to the inertia forces exerted on said abutments, an operating lever pivoted on said casing means and rockably moved in a plane perpendicular to the plane of rotation of the casing means in response to the movement of said follower, a member shiftable in either direction along an axis coincident with the axis of rotation of said casing means in re-. sponse to the movement of said operating lever, and non-rotative control means operated in response to the movement of the last said member.

11. A fluid type inertia device comprising casing means having an annular chamber in which a body of liquid is confined, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, two flexible diaphragms secured in said casing means in spaced relation along a common axis perpendicular to the plane of rotation of the casing means and t a certain radial distance from the axis of rotation of the casing means, said two diaphragms being subject to the inertia force of the body of liquid acting in opposite directions respectively upon a change in the rotational speed of the casing means and being of substantially the same effective pressure areas whereby the centrifugal forces of the body of liquid acting thereon are balanced, a follower interposed between said diaphragms and shiftable in opposite directions from a normal centered position by the inertia forces of the body of liquid exerted on one or the other of said diaphragms, a lever pivoted on said casing means and rockably moved to either side of a normal position, in response to movement of said follower, in a plane perpendicular to the plane of rotation of the casing means, a switch operating plunger slidably movable on an axis coincident with the axis of rotation of the casing means and associated with said lever in a manner to be shifted responsively to the movement of said lever, and non-rotative switch means operatively respons iy e to movenenmmam smngtr;

12. A fluid t'yp ifi rtiadvicecdihprising casing means having an annular chamber in which a body of liquid is confined and terminating in two circumferentially spaced ends, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, two complemental casing members separably secured together and connecting the ends of said annular chamber, a flexible diaphragm secured in each of said complemental casing members in a manner to be subject on one side thereof to the inertia force of the body of liquid confined in said annular chamber and resulting from changes in the speed of rotation of the casing means, said diaphragms being disposed in spaced relation along a common axis radially spaced from the axis of rotation of the casing means in parallel relation thereto and perpendicular to the plane of rotation of the casing means, the arrangement of said diaphragms being such that said diaphragms are acted upon respectively by the inertia force of the body of liquid acting in opposite directions, said complemental casing members cooperating to form a bore between said diaphragms, a follower slidably supported in said bore in interposed relation between said diaphragms and shiftable in response to movement of said diaphragms, an operating lever pivoted on said casing member and cooperating with said follower in such a manner as to be shifted rockably in a plane perpendicular to the plane of rotation of the casing means in response to movement of said follower, an operating plunger shiftable on an axis coincident with the axis of rotation of the casing means and cooperating with said operating lever in such a manner as to be shifted responsively to movement of said lever, and non-rotative control means cooperating with said plunger and operatively responsive to movement thereof while said casing means is rotating.

13. A fluid type inertia device comprising casing means having an annular chamber, a body of liquid confined in said chamber, said casing means being rotatable on an axis that intersects the center of curvature of the annular chamber, two separately movable abutments arranged in spaced coaxial relation on an axis perpendicular to the plane of rotation of the casing means and parallel to the axis of rotation of the casing means and respectively subject to the oppositely directed inertia forces of the body of liquid in said annular chamber resulting from a change in speed of rotation of the casing means, control means operatively responsive to the movement of said diaphragms, and valve means interposed in the annular chamber of the casing means in a manner to permit circulatory rotational movement of the annular body of liquid with respect to said casing means when the casing means rotatively decelerates at a rate exceeding a certain rate, whereby the inertia force of the annular body of liquid is exerted continuously on one of said diaphragms as long as the rotational speed of the casing means is less than the rotational speed of the annular body of liquid.

14. A fluid type inertia device comprising casing means providing an annular chamber having two circumferentially spaced ends, and being rotatable on an axis that intersects the center of curvature of the annular chamber, two complemental casing members separably secured together for connecting the ends of said annular chamber, a flexible diaphragm secured in each of said complemental casing members and disposed in spaced coaxial relation on an axis perpendicular to the plane of rotation of the casing means, said diaphragms being respectively subject to oppositely directed inertia forces of the body of liquid resulting from a change in the rotational speed of the casing means, a follower slidably supported in said complemental casing members between said diaphragms and shiftable to either side of a normal centered position in response to the inertia force of the body of liquid exerted on said diaphragms, control means operatively responsive to the movement of said follower, and loaded check valve means in each of said complemental casing members respectively subject to the oppositely directed inertia forces of said annular body of liquid and effective to establish communication between the two ends of said annular chamber in response to a predetermined inertia force resulting from the rotative deceleration of the casing means at a rate exceeding a certain rate, whereby to permit the body of liquid 

